1. Field
One or more embodiments of the present disclosure relate to a composite anode active material, an anode and lithium battery including the composite anode active material, and a method of preparing the composite anode active material.
2. Description of the Related Technology
Lithium batteries are used in various applications due to their high voltage and high energy density characteristics. Lithium batteries for devices such as electric vehicles should be operable at high temperatures, be able to charge or discharge a large amount of electricity, and have long-term usability. Thus, they should have high thermal stability, high-rate characteristics, and a long lifetime.
Lithium batteries may include carbonaceous materials as an anode active material. Carbonaceous materials are porous and stable with little volumetric change during charging and discharging. However, carbonaceous materials may lead to a low-battery capacity due to the porous structure of carbon. For example, graphite in the form of LiC6 has a theoretical capacity density of about 372 mAh/g.
Metals that are alloyable with lithium may be used as anode active materials with high electric capacity relative to carbonaceous materials. Examples of the metals that are alloyable with lithium include silicon (Si), tin (Sn), and aluminum (Al). However, these metals easily degrade, and thus batteries including such materials may have a relatively short lifetime. For example, degradation may occur with repeated charging or discharging of metals such as tin. The tin may be in the form of particles where aggregation and crushing of tin particles may be repeated, and thus, the Sn particles may be electrically shorted.
Additionally, lithium batteries may undergo thermal runaway due to short circuits.
Therefore, there is a need to develop lithium batteries with improved initial efficiency, discharge capacity, and lifetime characteristics.